Control systems for controlling traffic signals installed on roads have been used such that the display operations of the controlled traffic signals help to prevent traffic accidents and to make traffic smoother.
Among such control systems is, for example, a control system proposed to control traffic signals based on information on how long vehicles are forced to wait before the traffic signals, information on the number of vehicles which are passing by the traffic signals, and the like (see Japanese Patent Application Publication No. 2015-76046, for example).